What Causes Elevated Mean Platelet Volume (MPV)
Elevated MPV is primarily caused by conditions involving increased platelet turnover or destruction, myeloproliferative disorders, and certain inflammatory or metabolic conditions. 1
Primary Pathological Causes
Myeloproliferative Disorders
- Essential thrombocythemia, polycythemia vera, primary myelofibrosis, and chronic myeloid leukemia are major causes of elevated MPV. 1
- In polycythemia vera specifically, platelet abnormalities including altered size occur alongside qualitative platelet defects such as abnormal activation and altered glycoprotein expression. 2
- These disorders show defective TPO clearance due to reduced c-mpl membrane expression, leading to inappropriately normal or elevated TPO levels despite increased platelet mass. 2
Platelet Destruction States
- Immune thrombocytopenia (ITP) and disseminated intravascular coagulation (DIC) consistently show elevated MPV values. 1
- When MPV is high with low platelet count, hyperdestructive causes are present in essentially all cases. 3
- The elevated MPV reflects compensatory production of larger, younger platelets from the bone marrow in response to peripheral destruction. 3
Hematologic Disorders
- Post-hemorrhagic states, hemolytic anemia, and rebound thrombocytosis after treatment of thrombocytopenia cause elevated MPV. 1
- Post-splenectomy or functional hyposplenism results in elevated MPV due to loss of splenic sequestration of larger platelets. 1
- Heterozygous thalassemia shows high MPV with normal platelet count in the majority of cases. 3
Secondary and Metabolic Causes
Cardiovascular Risk States
- Elevated MPV is an independent cardiovascular risk factor associated with acute coronary syndromes, stroke, and myocardial infarction. 4, 5, 6
- Larger platelets are more reactive, with elevated MPV associated with shortened bleeding time and increased thromboxane B2 levels. 5
- Obesity, diabetes mellitus, and metabolic syndrome are associated with increased MPV values. 5
Inflammatory Conditions
- Inflammation and infection can cause high MPV with high platelet count. 3
- Growth factors and cytokines elicit production of larger, more reactive platelets in bone marrow during inflammatory states. 5
Physiological Causes
- Pregnancy causes temporary MPV elevation due to hormonal influences. 1
- Exercise-induced changes may transiently increase MPV. 1
- Aging is associated with gradually increasing MPV values. 1
Critical Diagnostic Considerations
Pre-analytical Variables
- Time between blood collection and analysis significantly affects MPV measurement. 1
- In conditions with increased hematocrit (like polycythemia vera), standard anticoagulant amounts with reduced plasma volume can artificially affect platelet parameters. 1
Inappropriately Low MPV
- When MPV is inappropriately low for the platelet count (whether high, normal, or low), consider sepsis, splenomegaly, aplastic anemia, chronic renal failure, or myelosuppressive drug therapy. 3
- This pattern indicates marrow hypoplasia or cytotoxic drug effects. 3
Clinical Approach
Initial Evaluation
- Serial measurements of MPV are more valuable than isolated readings to establish chronicity and monitor disease progression. 1, 7
- Complete blood count with review of platelet parameters should be the initial step. 8
- Correlate MPV with platelet count to categorize into one of nine diagnostic categories (high/normal/low MPV × high/normal/low platelet count). 3
Risk Stratification
- In patients with acute coronary syndromes, elevated MPV independently predicts mortality and composite cardiovascular endpoints. 6, 9
- The combination of elevated MPV and aspirin resistance confers particularly high risk for death and myocardial infarction. 4
- In polycythemia vera, monitoring MPV alongside other parameters helps assess disease activity and thrombotic risk. 1, 8